Tris (phenyl chloroethyl) phosphite



TRIS(PHENY L CHLOROETHYDPHOSPHITE John A. Pianfetti, South Charleston, W. Va., and Gennady -M. Kosolapotf, Auburn, Ala., assignors to Food Machinery and Chemical Corporation, New York, N. Y.,

- a corporation of Delaware No Drawing. Application October 7, 1955 Serial N0. 539,260

1 Claim. (Cl. 260-461) This invention relates to a new composition of matter,

novel method of preparing same, and its use as a gasoline ignition control additive.

The need for improved gasolines has been spurred since the end of World War II by the automotive industrys race to produce more and more powerful internal combustion engines. To achieve this greater horsepower, engine manufacturers have steadily increased cylinder compression ratios to the point where they now average 7.5 to 1.

One of the factors necessary to achieve maximum operating efiiciency from these high compression engines is that the ignition of the fuel-air mixture takes place at the moment of greatest compression.

,,As engines became more powerful, they have demanded higher octane fuel which could be manufactured only with an increase in the tetra-alkyl lead content. The use of these organic lead compounds in gasoline leads to the formation, during combustion, of lead salts and salts of other metals which catalyze the oxidation of carbonaceous residues from fuel'and oil and lower the ignition temperature of the carbon residues so that there is created glowing particles that ignite the fuel-air charge prematurely. The ignited deposits act as hot spots within the chamber and pre-ignite the fuel mixture before it reaches the point of greatest compression.

Heretofore, it has been the practice of the art to add to fuels containing organic lead compounds, a halohydrocarbon for the purpose of converting the lead into lead halides volatile at the combustion temperature and which would be swept out with the exhaust gases. These compounds are known as scavengers.

Inactual practice, however, the formation of lead oxyhalides and lead oxides as well as the volatile'lead halides cannot be avoided and deposits of lead compounds are found in the combustion chamber even when such scavengers are employed.

It is an object of the instant invention to provide a new composition of matter which may be employed as a gasoline additive. It is another object of this 'invention to provide a new composition of matter which will aid in the suppression of the pre-ignition characteristics of the fuel-air mixture. It is a further object of this invention to provide a novel means for preparing this new composition of matter. Further objects will appear-as a description of this invention unfolds.

We have discovered a certain organophosphorus compound having properties which renders it suitable for Un fi d S ews Pate to the lead compounds that form in the combustion cham- I ICC bet, absent the organo-phosphorous compounds of this invention. Thus, an increase in the ignition temperature of the cylinder deposit would likewise decrease thetendency of the deposit to pre-ignite the fuel-air mixture.

The terms, ignition temperature and glow point, are meant to be synonymous for the purposes of this specification unless a contrary intention is shown.

It is reported by those skilled in the art, that the glow point of combustion chamber deposits is directly related to the number of pre-ignitions occurring in the chamber.

The organo-phosphorus compound which we have discovered as suitable for use in accordance with this invention is tris (phenyl chloroethyl) phosphite. The structural formula for said compound is as shown below:

(C H CHClCH O) P The compound of the instant invention was prepared in a novel manner. The novel manner of preparation involved the reaction between styrene oxide or phenyl I is known as phenyl oxirane.

EXAMPLE I The apparatus used for this run was a three-necked flask fitted with a stirrer, thermowell, reflux condenser and a calibrated addition funnel.

The flask was charged with 113 parts of phosphorus trichloride and from the calibrated addition funnel was added 310 parts of phenyl oxirane (styrene oxide). The oxirane was added over a period of an hour while main taining the temperature of the reaction mass at about 25 C.

Upon completing the addition of the oxirane, the pressure in the system was reduced for a short interval of time to 2 mm. Hg in order to remove any traces of oxirane.

The product, tris.(phenyl chloroethyl) phosphite obtained in near quantitative yield had a specific gravity of 1.255 35/ 4 C. and a refractive index of 1.5713 D/25" C.

Calculated for C H O PCl P=6.2%, Cl=21.4%.' Found P=5.9%, Cl=22.2%.

Preliminary testing of this compound involved the common gasoline acceptance tests including: solubility of compound in gasoline, water tolerance,- gum formation and copper corrosion.

The first test, gasoline solubility, was conducted to determine at least qualitatively whether the organophosphorus compound was soluble in gasoline. This determination was made by measuring the light transmittancy of the gasoline both with and without the addition of the organophosphorus compound.

Solution which contained 0.03 volume percent of the phosphorus compound was prepared by adding 0.03 ml. of the compound to ml. of a premium gasoline.

After a short shaking and standing period the solution was transferred to an optical cell and the light transmittance of the solution measured. This value was com-- pared to the value for the premium gasoline which did not contain an additive.

A decrease in the light transmittance of the base fuel of 1% .or more indicates that the additive is sufl'iciently soluble for'th'epu'rp'os'e' 'oftliis invention.

The water tolerance was determined by following the proceduredetailed in ASTM D-1094-52.

" "The gum formationwas' determined by employing the copper dish method set forth infASTM D9l0..52T, Secion 9].

'T he copper corrosion test was conducted in accordance with the instructions stated in ASTM Dl30-53T.

The results of the above'tests are tabulated in Table I. The compounds, tris(phenyl chloroethyl) phosphite and tricresyl phosphate are represented by the abbreviations TPCEP and TCP in Tables I and II. A The inclusion of the compound, tricresyl phosphate, in the tables of the instant specification is for the purpose of comparing the compounds of the instant invention with that of a known gasoline predgnition additive.

An analysis of Table I shows the compound of the instant invention to be compatible with gasoline in so far as the common acceptance tests are concerned.

As mentioned previously, a definite correlation exists between the glow point of the cylinder residues and the number of preignitions.

Set forth below is the method employed in determining the glow point of the compound of this invention.

A synthetic engine deposit which contained 38.3% lead sulfate, 33.1% lead oxide, 7.7% lead chloride, 5.9% lead bromide and 15.0% carbon black was prepared by adding the approximate amounts of the several compounds together and mixing in a mortar and pestle. To a Pyrex Petri dish, W in. high and /2 in. in diameter was added 0.40 g.:0.1 g. of the synthetic deposit. Over this was burned in 100 ml. portions, gasoline which contained 0.03 volume percent of the several organophosphorus compounds tested. The amount of additive used was dependent on the phosphorus content of the organophosphorus compound. Enough phosphorus was used to theoretically convert all the lead in the synthetic deposit to lead phosphate. Air was introduced into the gasoline during the burning operation at 2500 cc. 2. minute in an attempt to convert some of the carbon given off during burning to oxides of carbon. An iron-constantin thermocouple was also placed in the burning fuel in order to obtain some idea as to the temperatures that occurred in the burning step. The majority of the gasoline burned between 150200 C. and the end gases, approximately 5-l0%, burned between 350 and 450 C. After burning was finishedthe deposit was scraped from the bottom and the inside wall of the dish. and this material then mixed in a mortar and pestle. A glow point determination was then made on the treated deposit.

The apparatus for a glow point determination consisted of a copper block, 3 in. in length by 2 in. in diameter. A A in. wide collar was at one end of the block. Two vertical holes, 2.5 in. long and cm. in diameter were drilled in the block. The block was heated by a 9 in. by 8 in. electric heating shell which was encased in aluminurn. The deposit wasplaced in a Pyrexheating boat which was: 1 in. tall and .10 cm. in diameter. Airwas metered through a rotameterand jetted onto the deposit through a steel hypodermic-needle. The needle extended 2%). inches inside the drilled. hole; The temperature was WbiQ xt nded. i toihe epo i In a typical experiment 0.2 g. of deposit was placed in a Pyrex boat and packed lightly into the Pyrex container. The thermocouple was placed in the deposit and air introduced at the rate of 200 cc./min. The variac which controlled the heating rate was set at 80 volts and was kept at this reading through the experiment. Temperature readings were taken every 10 minutes until 40 minutes had elapsed. After 40 minutes readings were taken in 0.5 to 1.0 minute intervals and the degree centigrade resulting from a sudden increase in temperature was taken as the glow point of the deposit.

The results of the above determination are recorded in Table II.-

T able-II Additive: Average glowpoint, C.

TPCEP 350 TCP 327 None 309 The novel additive of the present invention may beused inconjunction with the previously mentioned halohydrocarbons.

Examples of these halohydrocarbons are ethylene dibromide or dichloride, acetylene tetrabromide, 2,2,3-trichlorobutane, 2-chloro-2,3-dibromobutane, and the dibromomtoluencs. Mixtures of these halohydrocarbons, such as a mixture of ethylene dibromide and ethylene dichloride, may also be used. In general halohydrocarbons having a vapor pressure in the range of 0.1 mm. to 100 mm. mercury at 50 C. are capable of being used. It is desirable that the combined organo-phosphorus and halohydrocarbons contain not more than about by weight of the halohydrocarbons.

In general, the quantity of additives required in the fuel is that necessary to convert (theoretically) all the lead present as tetra-alkyl lead, into the corresponding lead halide and lead salt of the phosphite. Such a quantity is referred to as 1 theory. Greater or smaller quantities may be employed in some circumstances depending upon the particular components of the fuel and the type of engine in which it is intended to be used. In fact, one of the merits of the present invention is that it allows greater variations in the quantity of additive employed than is permissible when a halohydrocarbon is used as the sole additive. Even small excesses of halohydrocarbon additives are detrimental in such circumstances whereas with the additives of this invention a substantial excess can be tolerated without adverse results. The preferred range of total additive content of the fuel is from 0.9 to 1.2 theories.

Both the fuels and the composition suitable for addition to fuels provided by this invention may advantageously contain further compounds known to exert a stabilizing and/or anti-oxidixing effect on hydrocarbons of the gasoline boiling range. In this connection, 2,4-dimethyl- 6-tertiary butyl phenol is a particularly useful additive, other compounds such as hydroquinone, 2,6-di-tertiarybutyl-4-methyl, phenol, N-phenyl-a-naphthylamine and N,N-dibutyl-p-phenylenediamine may be employed.

While the invention has been described with special reference to tetra-ethyl lead, it can be applied equally well to other tetra-alkyl lead anti-knock agents, such'as ethyl-trimethyl lead, diethyl-dimethyl leacL tri-ethylmethyl, lead and tetramethyllead.

The fuels of this invention may be compounded by hyd'rocarbon additive and the whole composition blended into the fuel. Again the organo-phosphorus additive may be added to an unleaded gasoline and the tetra-alkyl lead fluid containing a halohydrocarbon scavenger added subsequently;

Alternatively, the organophosphorus may be in- Pursuant to the requirements of the patent statutes, That which is claimed as patentably novel is: the principle of this invention has been explained, and Acomposition of matter, tris(phenyl chloroethyl) phosexemplified in a manner so that it can be readily pracphite ticed by those skilled in the art, such exemplification including what is considered to represent the best embodi- 5 References Cited in the file of this patent ment of the invention. However, it should be clearly UNITED STATES PATENTS understood that, within the scope of the appended claim, the invention may be practiced by those skilled in the 1,936,985 Lommel et a1 1933 art, and having the benefit of this disclosure, otherwise 2226552 Conan fit 1940 than as specifically described and exemplified herein. 10 2'405'560 Campbell 1946 2,427,173 Withrow Sept. 9, 1947 2,728,790 Sroog Dec. 27, 1955 

